1. Field of the Invention
The present invention relates to a vehicle-onboard electronic toll collection or ETC communication apparatus which is mounted on a motor vehicle or an automobile or a car for conveying to a driver of the motor vehicle toll charge/payment information interchanged or exchanged with electronic toll collection or ETC system facility installed at a toll gate in the form of a displayed image and a voice message, respectively.
2. Description of Related Art
For having better understanding of the present invention, description will first be made in some detail of a conventional vehicle-onboard ETC apparatus known heretofore.
FIG. 9 is a block diagram showing schematically a general arrangement of a hitherto known vehicle-onboard ETC apparatus. Referring to the figure, reference numeral 1 denotes an antenna mounted on a motor vehicle (hereinafter referred to also as the vehicle-mounted antenna) for interchanging or exchanging (i.e., receiving/sending) the ETC-relevant information such as toll gate position information, toll charge/payment information, ID code information inherent or specific to the motor vehicle and the like with a toll collection transaction antenna (also referred to as the on-road overhead antenna) installed at the toll gate station of a toll road (not shown). Further, reference numeral 2 denotes a cable for the vehicle-onboard ETC apparatus (hereinafter this cable will be referred to as the vehicle-mounted cable) through which the ETC-relevant information is transferred between the vehicle-mounted antenna 1 and the vehicle-onboard ETC apparatus denoted generally by reference numeral 10.
As can be seen in FIG. 9, the vehicle-onboard apparatus 10 is comprised of a transmitter/receiver unit 3 for interchanging by radio waves the ETC-relevant information with a corresponding unit of the ETC communication facility or equipment installed at the toll gate station through the medium of the vehicle-mounted antenna 1 and the on-road overhead antenna, a control unit 4 for generating the ETC-relevant information to be sent to the ETC equipment of the toll gate station through the transmitter/receiver unit 3 while processing the ETC-relevant information received through the transmitter/receiver unit 3 into a signal for displaying a corresponding image, a manipulating unit 8 for performing signal input/output operations, input/output signal gain setting operations and others for the control unit 4, a display device 5 designed for displaying the received ETC-relevant information as an image while displaying the ETC-relevant information sent to the toll gate from the vehicle-onboard ETC apparatus as an image for the monitoring purpose and a power supply source 7.
Parenthetically, the manipulating unit 8 and the display device 5 cooperate to constitute a man-machine interface unit which serves as an intermediation medium for enabling communication between the vehicle-onboard ETC apparatus 10 and the driver of the motor vehicle.
FIG. 10 is a block diagram showing generally a circuit arrangement of the transmitter/receiver unit 3 known in the art.
Referring to the figure, the transmitter/receiver unit 3 is comprised of a detector diode D for detecting the ETC-relevant information signal emitted from the on-road overhead antenna A1 installed at a toll gate TG and received by the vehicle-mounted antenna 1, a detecting circuit 3-1 for detecting the level of the received signal as detected by the detector diode D, a demodulating circuit 3-2 for demodulating the received signal as detected to thereby restore the original ETC-relevant information which is then supplied to the control unit 4 as the received data, and a modulating circuit 3-3 for modulating the ETC-relevant information generated by the control unit 4 and outputted therefrom into a signal which is then fed to the vehicle-mounted antenna 1.
In this conjunction, it should be mentioned that the control unit 4 is so designed or programmed as to process the ETC-relevant information acquired after demodulation through the demodulating circuit 3-2 when the detection signal of a level higher than a predetermined one is inputted from the detecting circuit 3-1. More specifically, the ETC-relevant information sent from the overhead antenna A1 is received by the vehicle-onboard ETC apparatus to be processed by the control unit 4, only when the electric field intensity of the radio waves carrying the ETC-relevant information is higher than a predetermined level. In this way, communication between the vehicle-onboard ETC apparatus and the ETC system equipment installed at the toll gate TG can be carried out within a narrow range of radio-wave coverage area (service area), while erroneous communication with an adjacent antenna (i.e., other on-road overhead antenna) can be excluded. Thus, the toll collection transaction or toll charge/payment processing can be carried out essentially without fail.
Next, description will turn to operation of the conventional vehicle-onboard ETC apparatus of the structure described above.
By way of example, it is assumed that a motor vehicle or car equipped with the ETC apparatus 10 runs beneath the overhead antenna A1 installed at the toll gate TG. Then, the vehicle-onboard ETC apparatus 10 receives the radio wave signal carrying the information concerning the toll gate identifier which the motor vehicle currently is passing through and the toll collection information code from the ETC equipment installed at the toll gate through the medium of the overhead antenna Al and the vehicle-mounted antenna 1. The control unit 4 incorporated in the vehicle-onboard ETC apparatus 10 processes the received signal to recognize discriminatively the toll gate identifier as well as the toll collection information code, the results of which are displayed as visible information or image on the display device 5.
The driver of the car can thus confirm that his or her car is passing through a toll gate station concerned and that the toll collection processing (i.e., toll charge/payment processing) has been started by observing the screen image on the display device 5.
Furthermore, upon identification of the toll collection code being received, the control unit 4 reads out the information such as the ID number intrinsic to the motor vehicle or car concerned from an internal memory (not shown), which information is then supplied to the modulating circuit 3-3 to be thereby modulated for transmission to the overhead antenna A1 of the toll gate TG from the vehicle-mounted antenna 1.
The ETC system facility installed at the toll gate TG recognizes discriminatively the information such as the ID number and others, whereon the processing for settlement of the toll charge/payment is automatically executed for the bank account of the owner of the motor vehicle passing through the toll gate TG.
As will now be appreciated from the foregoing description, the conventional vehicle-onboard ETC apparatus (ETC-relevant communication apparatus) is so arranged as to display the ETC-relevant information interchanged through radio-wave communication between the vehicle-onboard apparatus and the ETC system facility of the toll gate in terms of image on the display device so that the driver can visibly confirm the ETC-relevant information. In that case, however, the driver""s sight line will be displaced to the display screen from the forward direction in which the motor vehicle is running, thus giving rise to a problem that the driver is very likely to be deprived of his or her attention toward the forward direction at least for a moment.
As an approach for solving the problem described above, it is conceivable to provide additionally or separately a voice message output apparatus for messaging the ETC-relevant information in a voice or audibly. In that case, when the voice output apparatus dedicated for messaging audibly the ETC-relevant information is provided in addition to an audio signal output apparatus of an existing car audio system, a large proportion of area of a front panel of the motor vehicle will be thereby occupied, incurring limitation to installation of other vehicle-onboard devices and instruments.
Besides, since the vehicle-onboard ETC apparatus and the existing car audio system are functionally independent of each other, at least two external speakers will exist internally of the car when the vehicle-onboard ETC apparatus equipped with the voice message output function is installed. Needless to say, installation of these two speakers will impose limitation to the possibility installation of other vehicle-onboard devices and instruments.
Furthermore, when the ETC apparatus is to be installed on a motor vehicle, it is required to mount temporarily the vehicle-mounted antenna at a location where the reception sensitivity is considered to be favorable, whereon the field intensity for reception of the ETC-relevant information signal is measured by using a specific meter dedicated to this end. Thus, the ordinary users will encounter not a little difficulty in searching the mounting position of the vehicle antenna at which the reception field intensity, i.e., field intensity for reception of the ETC-relevant information, is favorable, giving rise to another problem.
In the light of the state of the art described above, it is an object of the present invention to solve the problems mentioned above by providing an ETC apparatus which is capable of messaging to the driver of a motor vehicle the ETC-relevant information in both image and voice without need for appreciable extension or modification of hardware structure and which is additionally capable of discriminatively determining the field strength or intensity for reception of the ETC-relevant information with the aid of voice and image without resorting to use of any specific dedicated measuring device.
In view of the above and other objects which will become apparent as the description proceeds, there is provided according to a general aspect of the present invention a vehicle-onboard ETC apparatus mounted on a motor vehicle, which apparatus includes a communication means for interchanging toll charge/payment information with a toll gate station equipped with ETC communication facility when the motor vehicle passes through the toll gate station, a signal conversion means for converting the toll charge/payment information received into an image signal and a voice signal, a display means for displaying the image signal resulting from the conversion, and a voice signal output means for outputting the voice signal resulting from the conversion to an audible signal conversion means.
By virtue of the arrangement of the vehicle-onboard ETC communication apparatus described above, the toll charge/payment information can be confirmed by the driver without being deprived of the forward view field in the course of passing through the toll gate, whereby safety driving operation can be ensured.
In a preferred mode for carrying out the invention, the voice signal output means may be arranged so as to convert the inputted voice signal into a voice through audible signal conversion means of an existing audio system installed internally of the motor vehicle.
With the arrangement of the vehicle-onboard ETC communication apparatus described above, the whole apparatus can be implemented relatively inexpensively at a low cost, to an advantageous effect.
In another preferred mode for carrying out the invention, the voice signal output means may include a signal switching means which is so designed as to output through the audible signal conversion means an audible signal supplied from the existing audio system when the voice signal is quiescent, while upon inputting of the voice signal, the signal switching means is changed over to select the voice signal for outputting the voice signal through the audible signal conversion means.
Owing to the arrangement of the vehicle-onboard ETC communication apparatus described above, the whole apparatus can be implemented inexpensively at a low cost, to another advantageous effect.
In yet another preferred mode for carrying out the invention, the signal conversion means may include a first conversion means for converting a signal level of toll charge/payment information received through the communication means into a field intensity for reception of the toll charge/payment information, and a second conversion means for converting the field intensity into an image signal such that a shape of an image represented by the image signal varies in dependence on change of magnitude of the field intensity, the image being displayed on the display means.
With the arrangement of the vehicle-onboard ETC communication apparatus described above, the field intensity for reception of the ETC-relevant information can easily be measured, to yet another advantageous effect.
In still another preferred mode for carrying out the invention, the signal conversion means may include a first conversion means for converting a signal level of toll charge/payment information received through the communication means into field intensity for reception of the toll charge/payment information, and a third conversion means for converting the field intensity resulting from the conversion into a numerical value corresponding to change of the field intensity and then converting the numerical value into an image signal to be displayed on the display means.
With the arrangement of the vehicle-onboard ETC communication apparatus described above, the field intensity for reception of the ETC-relevant information can accurately be measured, to yet another advantageous effect.
In a further preferred mode for carrying out the invention, the signal conversion means may include a fourth conversion means for converting the field intensity for reception of the toll charge/payment information as outputted from the first conversion means into an acoustic signal the level of which varies in dependence on change of the field intensity, the acoustic signal being outputted as a sound from the audible signal conversion means.
Owing to the arrangement of the vehicle-onboard ETC communication apparatus described above, the location where the field intensity for reception of the ETC-relevant information can be determined with high effective means.
The above and other objects, features and attendant advantages of the present invention will more easily be understood by reading the following description of the preferred embodiments thereof taken, only by way of example, in conjunction with the accompanying drawings.